Botanical name: Ageratina adenophora Family: Asteraceae (Sunflower family)
Synonyms: Eupatorium adenophorum, Eupatorium glandulosum
Native to Central America, Catweed is an erect, bushy, leafy, many-stemmed herb, growing to 2 m tall. It commonly occurs in disturbed areas. Leaves are opposite, soft, thin, shaped like a triangle or rhombus, with a toothed edge and conspicuous veins. They are dark green on the upper surface, lighter underneath, and may be slightly hairy; 4-12cm long, 3-9cm wide. Flowers profusely in spring and summer, producing dense clusters of white sticky hairy flowers, 5-8 mm in diameter, at the ends of the branchlets. Seed production is enormous - 10,000 to 100,000 per year when mature. The seeds are very small, light, brown to black, with a 4mm 'parachute' of white hairs, mid to late spring. Germination rates are high.
Identification credit: Tony from Sydney
The flower labeled Catweed is ...